Reduce Exceptions thrown during type conversions.

There are tons of places where null, blank or empty strings are being
converted to primative types (like int,, long, etc) or other ValueTypes
(like Guid, DateTime, etc.). When this is attempted, Exceptions are
thrown (and caught/swallowed) to allow for value defaulting. Since this
happens all the time in normal operation, tons of Exceptions are being
thrown. By switching to the TryParse methods available on all primative
types and the interesting ValueTypes, we can greatly speed the
processing of content data.
Merge pull request #172 from IDisposable/6.2.0

Reduce Exceptions thrown during type conversions.
Merge remote-tracking branch 'origin/6.2.0' into 6.2.0-membershipprovider